Related Clues:

• Subterranean pest
• Stratego piece
• Maxwell Smart, for one
• Spymaster's worry
• Watch covertly
• Snoop (on)
• Blemish
• Microfilmer, maybe
• You could see it on Marilyn's face
• Security problem
• ''The Wind in the Willows'' character
• Sneak a peek
• Double agent
• CIA operative
• Furry tunneler